Photocatalytic behavior for removal of methylene blue from aqueous solutions via nanocomposites based on Gd2O3/CdS and cellulose acetate nanofibers

Abstract

Efficient cleaning of contaminated water by photocatalysis has become an effective strategy in recent years due to its environmental and ecological designation. Cadmium sulfate (CdS) is an excellent photocatalyst in the visible region but has low quantum efficiency. In order to increase the photocatalytic efficiency, CdS was modified with gadolinium oxide (Gd2O3) and combined with graphene oxide (GO) nanoparticles. The estimated crystallite size (Ds) for Gd2O3, CdS/Gd2O3, and CdS/Gd2O3@GO was 29.6, 11.6, and 11.5 nm, respectively. The degradation of methylene blue (MB) reaches the highest values after 60 min under visible light irradiation with a dye concentration of (0.25 ppm). Whereas in powdered composition the efficiency of dye removal has been enhanced under UV irradiation, it reduced by increasing the MB concentration to 0.50 ppm with visible light irradiation. In addition, the CdS with/without Gd2O3 and GO were integrated into electrospun nanofibrous cellulose acetate (CA) through the electrospinning technique. The compounds of Gd2O3, CdS/Gd2O3, and CdS/Gd2O3/GO were encapsulated into CA nanofibers for the degradation of MB under visible and UV irradiation. The apparent rate constant (k) achieves a value of 0.006, 0.007, and 0.0013 min−1 while the removal efficiency reaches 41.02%, 54.71%, and 71.42% for Gd2O3@CA, CdS/Gd2O3@CA, and CdS/Gd2O3/GO@CA, respectively, after 60 min under UV irradiation.

Microwave-Assisted Synthesis of Flower-like MnMoO4 Nanostructures and Their Photocatalytic Performance

“…Two types of control experiments were conducted by taking a blank dye (MB) solution of 1 × 10 −5 and a dye with MnMoO4 in dark conditions to compare the photocatalytic action of the material in the existence of light. The typical procedure of combining dye with a catalyst in the presence of light involves the addition of 100 mL of a 1 × 10 −5 M MB dye solution to a 250 mL beaker along with 50 mg of the catalyst (MnMoO4).The mixture of pollutant and catalyst was obtained in the dark, preventing contact with light, to achieve the adsorption-desorption balance of the photocatalyst and dye[38,39]. Among the above two reaction mixtures, the pure dye solution and the dye with the catalyst were maintained in the dark, the dye was set with light, and the material with dye was exposed to the visible light after half an hour while being constantly stirred with magnetic stirrer.…”